Pressure sensor

ABSTRACT

A pressure sensor apparatus includes: a plurality of pressure responsive chambers provided along a longitudinal dimension of the apparatus, and a pressure sensor device provided in each chamber which together provide a pressure profile in an anatomical cavity.

FIELD OF THE INVENTION

The present invention relates to pressure sensors and in particular topressure sensors that can be placed inside a human body. The pressuresensor preferably measures a pressure profile along a vaginal cavity,measuring both the intra-abdominal pressure and pelvic floor pressure.

BACKGROUND

There has been increasing interest in quantitatively investigating theassociation between abdominal pressure related to exercise and thedevelopment of urinary incontinence and pelvic organ prolapse (POP).Although it is well recognised that regular, moderate to intenseexercise is important for health and well-being, current recommendationsfor women either at risk of incontinence, POP, or post-surgery, areinconsistent and variable. It is assumed that an increase in IAP mayadversely affect the support structures of the pelvic organs or theintegrity of the surgical repair. However, there is littleevidence-based information to support these assumptions.

The aetiology of POP and urinary incontinence is multi-factorial, butultimately related to the inability of the pelvic support systems tocounteract pressure exerted by the abdominal contents, resulting indescent of the pelvic organs. Epidemiological studies suggest that womenare more likely to present with POP if they suffer from chronic cough,constipation, have a high body mass index, or undertake repeated heavylifting.

Abdominal pressure is generated by the gravitational loading of theabdominal contents, which are relatively incompressible. Therefore, inaccordance with Pascal's Law, the measurement of IAP in one location canbe assumed to represent the pressure throughout the abdomen, ignoringhydrostatic loading. Whilst the International Continence Society refersto abdominal pressure (P_(abd)), as that which surrounds the bladder inthe context of urodynamics, for the purposes of this patent applicationwe will use the term intra-abdominal pressure (IAP).

Thus, the measurement of IAP is commonly performed using either anintra-vesical (i.e., bladder) or intra-rectal pressure transducer, or arectal transducer placed intra-vaginally. Using these devices, pressuresare measured using fluid-filled systems, which use the fluid tophysically pass the pressure indication externally of the body. Thus thepatient is connected to a pressure measuring and recording device whichmeasures the pressure of the fluid. Pressure wave dampening and fluidinertia associated with fluid-filled systems are likely to causeartefacts that will decrease the sensitivity of measurement of pressure.Additionally, movement of the tubing itself will cause significantinaccuracies that can be of similar magnitude to the IAP being measured.These issues, and the low data sampling rates of current commercialsystems, make assessment of change in IAP during exercise difficult.Several studies that have used commercially available urodynamicssystems to measure increases in IAP during exercise have been limited bythe factors mentioned above, as well as by retention issues of thepressure sensor. In most studies, movements were restricted to exercisesthat could be performed whilst connected to the urodynamics system,again limiting the kind of exercise that could be assessed.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a pressure sensor which willat least go some way to overcoming disadvantages of existing systems, orwhich will at least provide a useful alternative to existing systems.

Further objects of the invention will become apparent from the followingdescription.

SUMMARY OF INVENTION

Accordingly in one aspect the invention may broadly be said to consistin a pressure sensor apparatus comprising:

a plurality of pressure responsive chambers provided along a firstdimension of the apparatus; and

a pressure sensor device provided in each chamber.

Preferably the chambers are arranged successively along the firstdimension such that the apparatus may simultaneously sense pressure tothereby sense a pressure profile along the first dimension.

Preferably each chamber comprises at least one pressure transmittingwall.

Preferably mechanical isolation means is provided between the chambers.In one embodiment the mechanical isolation means comprises a pressureresistant barrier between adjacent chambers. Preferably the pressureresistant barrier is sufficient to substantially prevent pressurechanges in one chamber affecting pressure in the adjacent chamber.

Preferably each chamber is filled with fluid. Preferably the pressuresensor device senses the pressure of the fluid in the chamber. In oneembodiment the fluid comprises air.

Preferably the apparatus further comprises a data transfer means, suchas a transmission means to transmit the sensed pressure from each sensorto a further apparatus. In one embodiment the further apparatus maycomprise one or more of a measurement, storage, or display apparatus.

In one embodiment the transmission means is provided distally from theplurality of chambers. In another embodiment the transmission means maybe located proximally to the plurality of chambers.

Preferably the apparatus further comprises a retention means. In oneembodiment the retention means comprises a retention contour which mayextend in a second dimension which is substantially transverse to thefirst dimension. The retention means may be a contour provided as one ormore ribs or wings dependent from the apparatus.

Preferably the apparatus includes an exit or funnel means. This maycomprise a data exit port, and/or support a tube or conduit within whichconductors may be located.

Preferably the apparatus comprises an intra-abdominal pressure sensingdevice.

Preferably the apparatus comprises an intra-vaginal device.

In another aspect the invention may broadly be said to consist in anintra-vaginal pressure sensor apparatus comprising:

a plurality of pressure sensors provided along a first dimension of theapparatus whereby a pressure profile can be determined along the firstdimension.

Preferably each pressure sensor device is provided in a chamber.

Preferably the chambers are arranged successively along the firstdimension such that in use the apparatus may sense a pressure profilealong the vagina.

Preferably each chamber comprises at least one pressure transmittingwall.

Preferably mechanical isolation means is provided between the chambers.In one embodiment the mechanical isolation means comprises a pressureresistant pathway between adjacent chambers. Preferably the pressureresistant pathway is sufficient to substantially prevent pressurechanges in one chamber affecting pressure in the adjacent chamber.

Preferably each chamber is filled with fluid. Preferably the pressuresensor device senses the pressure of the fluid in the chamber. In oneembodiment the fluid comprises air.

Preferably the apparatus further comprises a transmission means totransmit the sensed pressure from each sensor to a further apparatus. Inone embodiment the further apparatus may comprise one or more of ameasurement, storage, or display apparatus.

In one embodiment the transmission means is provided distally from theplurality of chambers. In another embodiment the transmission means maybe located proximally to the plurality of chambers.

Preferably the apparatus further comprises a retention means. In oneembodiment the retention means extends in a second dimension which issubstantially transverse to the first dimension. The retention means maybe provided as one or more ribs or wings dependent from the apparatus.

Preferably the apparatus includes an exit or funnel means. This maycomprise a data exit port, and/or support a tube or conduit within whichconductors may be located.

In another aspect the invention may broadly be said to consist in amethod of providing a pressure sensor apparatus, the method comprising:

providing a first part structure with a plurality of recesses;

providing a second part structure;

providing a pressure sensing device in each recess, and;

joining the part structures to thereby close the recesses and form aplurality of pressure responsive chambers.

Preferably the chambers are provided along a first dimension of theapparatus.

Preferably the part structures are flexible.

Preferably at least one of the part structures comprises a pressuretransmitting material.

Preferably the method includes filling each chamber with fluid.

Preferably the step of filling each chamber with fluid occurs prior tojoining the part structures.

Preferably the pressure sensor device senses the pressure of the fluidin the chamber. In one embodiment the fluid comprises air.

In another aspect the invention may broadly be said to consist in amethod of providing a pressure sensor apparatus, the method comprising:

providing a substructure with a plurality of recesses or openings;

providing a pressure sensing device in each recess or opening, and;

closing the recesses or openings with a pressure transmitting materialto form a plurality of pressure responsive chambers.

Preferably the recesses or openings are provided along a first dimensionof the substructure.

Preferably the substructure is flexible.

Preferably the pressure transmitting material is flexible.

Preferably the step of closing the recesses or openings comprisesovermoulding the substructure.

Preferably the method includes filling each chamber with fluid.Preferably the pressure sensor device senses the pressure of the fluidin the chamber. In one embodiment the fluid comprises air.

In a further aspect, the invention broadly provides a method ofmeasuring pressure in an anatomical cavity comprising simultaneouslysensing pressure at a plurality of locations along a first dimension ofthe cavity and recording the sensed pressure measurements to provide apressure profile.

Further aspects of the invention will become apparent from the followingdescription.

DRAWING DESCRIPTION

A number of embodiments of the invention will now be described by way ofexample with reference to the following drawings.

FIG. 1 is an isometric view of a flexible substrate which may be used toform apparatus according to the invention.

FIG. 2 is a photograph showing two partially complete embodimentsaccording to the invention, together with a processing apparatus.

FIG. 3 is a photograph showing moulds for forming another embodimentaccording to the invention.

FIG. 4 is a drawing of one of the moulds shown in FIG. 3.

FIG. 5 is a drawing of other of the moulds shown in FIG. 3.

FIG. 6 shows the package outline and pin configuration of a pressuresensor for use with the embodiments shown in FIGS. 3 and 4.

FIG. 7 is a drawing of a further embodiment of apparatus according tothe invention.

FIG. 8 shows the package outline and pin configuration of a pressuresensor for use with the embodiment shown in FIG. 7.

FIG. 9 is a drawing showing an embodiment ready for use.

FIG. 10 shows an axial volume image of the human female pelvic floorwith an inserted device according to an embodiment of the invention.

FIG. 11 is a plot showing the difference in pressure readings between areference sensor in a fluid filled chamber and a sensor sitting in amembrane covered, air-filled pocket is not constant during pressureincrease.

DETAILED DESCRIPTION OF THE DRAWINGS

Throughout the description like reference numerals will be used to referto like features in different embodiments.

Pelvic floor disorders, such as stress urinary incontinence (SUI) andpelvic organ prolapse (POP), are distressing and cost-intensiveconditions that affect more than 25% of the female population. Althoughthe exact mechanisms of POP and SUI are poorly understood, thedevelopment of such conditions are likely to alter the pressures actingon the vaginal wall, and thus change the vaginal pressure profile. Thereis little research on the change in the vaginal pressure profile inresponse to either surgical correction of POP or as a consequence ofpelvic floor muscle training. Recent reviews suggest that pelvic floormuscle training (PFMT) is an effective first line treatment for womenwith stress urinary incontinence, and mild POP. However, more than 30%of women are unable to effectively contract their pelvic floor musclesand PFMT is contingent on the exercises being performed correctly. Whenthese exercises are correctly performed, there is an increased pressurein the region of the pelvic floor muscles, while keeping abdominalpressure low.

The apparatus disclosed herein allows pressure within a mamallian body,in particular a human body to be sensed. The apparatus has particularapplication to sensing intra-abdominal pressure to provide an indicationor quantification of muscle activity. Approximately 30% of women indeveloped countries suffer from urinary incontinence and mild pelvicorgan prolapse. Pelvic floor muscle (PFM) exercises are effective in theprevention and treatment of these dysfunctions. To advise women onsuitable exercises and to control whether these exercises are performedcorrectly, PFM strength and abdominal pressure need to be assessed.

Additionally, after surgery, such as anterior vaginal repair or thelike, the pressure sensor of the present invention could providefeedback on the outcomes of the surgery.

In the following description the application of the pressure sensor ofthe present invention is to intra-abdominal pressure and use of thesensor within the vaginal cavity. However, the pressure sensor of thepresent invention could be used in any other body or anatomical cavity,such as, the anus, urinary tract, bowels or the like, to measurepressures.

The pressure sensor of the present invention is preferably a compliantintra-vaginal pressure sensing device that is able to record the vaginalpressure profile at rest, during PFMT and everyday activities. As aresult vaginal pressure profiles may be used as biofeedback for PFMT,being able to measure both abdominal and pelvic floor (PF) pressuresimultaneously, in addition to assessing the vaginal pressure profilepre- and post-surgery.

Additionally, the quantification of pelvic floor pressure and pressureprofiles will provide measurements of pelvic floor and abdominalpressure to help identify women at risk of Pelvic Prolapse or UrinaryIncontinence. Such an apparatus may also be used by physiotherapists andhealth providers to ensure pelvic floor exercises are being performedcorrectly

Referring to FIG. 1, a flexible substructure 1 is shown, which comprisesa first part of a pressure sensor apparatus. The substructure 1 may beformed from a relatively inert flexible material such as silicone or amaterial having similar properties. For example, a biocompatiblesilicone (e.g. MED-4960) may be used. The substructure 1 has a number ofopenings 2 which may be used to house pressure sensor devices as will bedescribed further below. To complete the apparatus, the substructure 1has a membrane attached to or moulded about either side, so that theopenings 2 become chambers within which individual pressure sensingdevices are housed. The material from which the membranes are formed(for example a silicone or similar material) allows pressure to betransmitted from the environment in which the apparatus is located intothe chamber. Thus the sensing devices are independently isolated inseparate chambers. The chambers are designed to be substantiallymechanically isolated from each other. For example, the pathway or wallregions between adjacent chambers are selected to provide a pressureresistant barrier or pathway between adjacent chambers. Preferably thebarrier provides mechanical isolation which is sufficient tosubstantially prevent pressure changes in one chamber affecting pressurein the adjacent chamber. The mechanical isolation between chambersresults in only a small change in pressure in each chamber when thearray is bent compared to the magnitude of the pressure changes during apelvic floor exercise. In a preferred embodiment a fluid such as air ispresent in each chamber, and the sensing devices detect or sense thepressure of this fluid.

Turning now to FIG. 2, another embodiment of substrate 1 is shown,including a pressure sensing device 3. In this example the pressuresensing device comprises a MS5803-02BA pressure sensor, for connectionto a processing/measuring device 4 comprising an Arduino Mega 2560board. A smaller processing/measuring device 22 is shown in FIG. 9 andis based on the Bluetooth Smart nRF51822 system on a chip from NordicSemiconductor. Returning to FIG. 2, to complete the apparatus, thesubstructure 1 has a membrane attached to the upper side covering overthe openings 2 that contain the sensing device 3. Another substructureembodiment 5 is shown having pockets 6 rather than openings 2 forreceiving the pressure sensing devices 3. The substructure 5 includes amembrane which is fabricated in the single moulding process. Thesubstrate 5 has a membrane in the top side and a second membrane in thebottom side and the pressure sensing device will respond to pressure oneither membrane.

When the substructure is fully assembled the pockets 5 become chamberswithin which individual pressure sensing devices are housed. Again, thematerial from which the membranes are formed (and/or the material fromwhich the substructure 5 is formed) allows pressure to be transmittedfrom the environment in which the apparatus is located into thecompleted chamber, that the pressure sensing device 3 that is housed ineach chamber can sense the pressure in the immediate environment, forexample the pressure at a location in an anatomical cavity in which theassembled apparatus is located.

Although the examples discussed in FIG. 2 are designed to provide eightchambers (i.e. eight pressure sensing devices), a greater or lessernumber of chambers may be provided. In some embodiments six chambers areprovided. It will be seen that the assembled apparatus is substantiallyelongate i.e. a first (length) dimension is greater than a secondtransverse (width) dimension. The chambers are arranged successivelyalong the first dimension which in this example is a longitudinaldimension of the apparatus. The array or row of chambers provided alongthe first dimension allows pressure measurements to be sensed orrecorded simultaneously by the sensing devices to thus allow a pressureprofile to be sensed or measured along that dimension. The chambers donot have to be arranged in a line as shown in the drawings.

In FIG. 3, two aluminium moulds 10, 11 are provided for anotherembodiment, or for moulding over the substructures referred to above,are shown. Each mould is seen more clearly in FIGS. 4 and 5. The mouldsallow the apparatus to be injection moulded using a biocompatiblesilicone (e.g. MED-4960).

The mouldable material may be provided in mould 11, and then mould 10 islocated (face down) over 11 so that one half of a resultant structure isprovided. The process is repeated to form the other half structure. Thesensing devices can then be placed in the recesses formed in a firsthalf. The second half is then bonded to the first half, thereby closingthe recesses to from chambers that contain the sensing devices.

As will be described further below, this example includes a retentionmeans or contour formed by one or more external regions of theapparatus, and an exit interface in the form or a funnel portion 16. Asimilar example is shown in FIG. 7, the primary differences between theembodiments being that the FIG. 7 embodiment has chambers with asubstantially square shape in plan view (whereas those in the FIG. 3, 4,5 embodiment are a rounded rectangular shape), and the FIG. 7 embodimentincludes an insertion means in the form of aperture 18 which may be usedwith an applicator to insert the device.

A sensing device (in this example a MS5611-01BA sensor) of the formshown in FIG. 6 may be used with the FIG. 3, 4, 5 embodiment. TheMS5611-01BA sensor is a high resolution altimeter sensor from MEASSwitzerland with SPI and I2C bus interface. This barometric pressuresensor is optimized for altimeters and variometers with an altituderesolution of 10 cm. The sensor module includes a high linearitypressure sensor and an ultra-low power 24 bit ΔΣ ADC with internalfactory calibrated coefficients. The MS5611-01 BA can be interfaced tomany different microcontrollers. The communication protocol is simple,without the need of programming internal registers in the device. Smalldimensions of only 5.0 mm×3.0 mm and a height of only 1.0 mm allow forintegration in mobile devices.

A sensing device (in this example a MS5803-01 BA pressure sensor) of theform shown in FIG. 8 may be used with the FIG. 7 embodiment. TheMS5803-01 BA sensor is a high resolution altimeter sensor fromMeasurement Specialties with SPI and I2C bus interface. The sensormodule includes a high linearity pressure sensor and an ultra-low power24 bit AZ ADC with internal factory calibrated coefficients. It providesa precise digital 24 Bit pressure and temperature value and differentoperation modes that allow the user to optimize for conversion speed andcurrent consumption. The MS5803-01 BA can also be interfaced to manydifferent microcontrollers.

The sensors may all be mounted on flexible PCBs.

An assembled apparatus which includes the FIG. 7 embodiment is shown inFIG. 10. As shown in that figure, the substructure 1 of the apparatushas been moulded over or otherwise incorporated in a flexiblebiocompatible material to provide chambers 7, each of which contains apressure sensing device 3. The retention contour in this embodimentcomprises protruding regions 14, 15 which protrude transversely to thefirst (elongate or longitudinal) dimension along which the chambers 7are provided. The retention contour may take other forms, for example asingle protruding rib or wing may be present, and the protrusion couldbe at a different location. Also multiple ribs/wings may be provided atdifferent angular locations. For example, two alternative embodiments ofthe pressure sensor apparatus are shown in FIG. 12. Here the retentioncontour is similar to that described above, but in 12(b) the protrudingregions 110 are more like rectangular regions extending either side ofthe body 100 of the apparatus, In FIG. 12(a) the retention contour 120comprises a plurality of ribs along the length of the body 130 on eitherside of the body.

The pressure sensor assembly may also be inserted into a detachablesheath. The sheath may provide protection from moisture ingress to theelectronics and keep the pressure sensor assembly clean. The sheath maybe supplied with different protruding regions 14, 15 of varying sizes toaid with retention. The sheath may be replaced every time the device isused, or on a regular basis. In the region of the pressure sensors, thesheath will be of a thin flexible material such as silicone rubber orlatex.

The exit/funnel portion 16 guides conductors 21 (for example a data busor FPC strip) out of the apparatus within a flexible tube 20 which maybe constructed from a soft silicon material for example. The conductors21 electrically connect the sensing devices 3 to an appropriate datatransfer means. In one example this may comprises a transmission meanssuch as a Bluetooth™ module for example. In other embodiments atransmission module may be proximal to the sensors (for example beingmoulded into a region adjacent to the sensor array). Various forms ofcommunication may be used, for example Bluetooth, Zigbee or Wifi radiosystems can be incorporated into the module 22. It will also be seenthat in some embodiments the apparatus may include a memory to storedata to be downloaded at a later time.

Transmission to a mobile device supports realtime feedback on thepressure profile during different conditions in the anatomical cavity inwhich the apparatus is located, for example during a pelvic floorexercise when the device is located in an intra-abdominal orintra-vaginal cavity. The access of the mobile device to the cloudallows feedback on performance compared to historical data and thesharing of outputs with other interested parties. Other interestedparties include clinical and social users.

A clip will enable the module 22 to be attached to undergarments tosecure the module during movement and exercise.

The apparatus may be used in the vagina to perform intra-abdominalpressure measurement. The materials and dimensions have been selected sothat when in place the pressure sensor matches the contours of thevaginal wall. The pressure sensor of the present invention is a mobileintra-vaginal pressure sensing device (IVPSD), to continuously measurethe vaginal pressure profile for evaluating the PFM performance. Theinformation recorded from these sensors will be carried along an SRI busexchange path 21, which will then be transmitted by a Bluetoothmicrocontroller 22 to a receiver or an app. Recorded pressures from thedevice are preferably sent via Bluetooth to an Android device, displayedby a user-friendly “app”. However, other means of display may be used,for example, on any appropriate graphical user interface, PC or thelike.

The pressure sensor of the present invention may be used to provide anextensive pressure profile along the vagina by incorporatingapproximately 6 sensors. The device can be used when a user is upright,walking or exercising.

Thus the present invention allows an array of measurements to beobtained along a pathway to provide a profile.

The profile gives information that quantifies the pressure that anindividual can produce through squeezing their pelvic floor muscles.Properties derived from the profile, such as the gradient, enablepatient status to be derived, and therefore the progression of theirstatus when the measurement is obtained at a later time. The later timemight be after a period of performing pelvic floor exercises, or after aperiod of professional treatment (e.g. physiotherapy or surgery).

The construction details presented show how two types of pressuresensors could be integrated into a flexible substrate that can belocated in the vagina easily. The pockets and openings enable theidentified sensors to respond to the pressure changes that will occur inthe vagina during a range of activities. Other sensors may also be ableto be used to quantify the pressure changes or at least provide apatient-specific baseline for the pressure profile in the vagina. Theadvantage of other sensors may be that the apparatus can be fabricatedon a flexible printed circuit board and lower the production cost. Anexample of another sensor is the force transducer from TekScan,FlexiForce A201. Another example is a printed circuit trace where theresistance or capacitance changes when a surface above the trace movescloser due to compression from a pelvic floor muscle squeeze. Thesealternate sensors may not allow the derivation of the pressure along thevagina accurately, but may be sufficient to show the pelvic floormuscles are being contracted correctly to perform pelvic floorexercises.

The IVPSD has been tested and is shown in position in the ultrasoundimage of FIG. 10.

The use of individual fluid filled chambers that incorporate fluidpressure sensing devices provides superior performance to otherconstructions. When the sensors are covered by a membrane or containedwithin a pocket of compressible fluid, then the recorded pressure willbe reduced compared to the pressure exerted on the outside surface ofthe membrane, as seen in FIG. 11. A calibration process is implementedto correct for the differences in pressure readings due to theencapsulation method used. The calibration method subjects the sensorsto at least two known pressure levels.

Additionally, an IVPSD 200 as shown in FIG. 13, having an array of eightpressure sensors 230 (individually numbered 1 to 8) to enablemeasurement of the pressure along the length of a vagina, was tested ona number of different female human subjects.

The sensors 230 were mounted on a flexible printed circuit board 210 toallow the device to conform to the anatomy of the vagina, withoutdistorting the vaginal walls. A soft biocompatible silicone (preferablyMED-4901, NuSil, however, other appropriate materials may be used) wasused as the encapsulating material or cover 220. In this embodiment, thearray of sensors has a total length of 80 mm and a maximum width of 20mm. The contoured edges cover a distance of 55 mm and are designed tosit within the rugae of the vaginal wall to reduce device movement. Alead 240 provides apparatus for data transfer from the flexible printedcircuit board 210 that connects to further apparatus comprising in thisexample a small electronics module (not shown) which is located outsidethe human body. For preliminary testing, the IVPSD 200 was connected toan SPI bus (USB-8452, National Instruments) and a computer. LabVIEWserved as the user-interface. Each pressure sensor sampled at a rate of140 Hz.

Each subject knew how to contract their pelvic floor muscles and had nosymptoms of POP. The IVPSD was self-inserted and the following tasksperformed: maximum PFM contractions (3×5 s), as many as possible rapidPFM contractions (15 s), Valsalva (3×5 s) and coughing (5×). Vaginalpressures profiles were recorded for all tasks. Baseline pressures wererecorded prior to each task. The raw data was analysed using MATLAB. Foreach task the maximum and mean pressures were calculated. For selectedtasks the rate of pressure change was also computed.

The IVPSD has a tail 250 and a head 260, shown in FIGS. 13 and 14. Thehead 260 of the device sits in use in the deep vagina, and the sensorsnear the head measure abdominal pressure. The tail 250 of the device islocated at the entrance of the vagina, the introitus.

Two of the subjects were vaginally parous and the other two werecaesarean parous. The test subjects reported that the IVPSD was easy toinsert and comfortable. Downward displacement of the IVPSD occurred onlyduring cough or valsalva, more so in the vaginally parous women.

Pressure profiles for each of Subjects 1 to 4 are shown in FIG. 14.Atmospheric pressure has been subtracted for the baseline pressure. Thebaseline pressures have been subtracted from the profiles. Each restingbaseline pressure profile was unique, although a drop in pressure in theregion of the PFM was recorded for all subjects, reaching nearatmospheric pressure at the introitus (see the illustration in FIG. 14showing the position of the abdomen and introitus in relation to thedevice). Distinctive vaginal pressure profiles were measured for eachtask and each subject. During PFM contractions the greatest increase inpressure was in the region of the PFM, shown by the sensors placedapproximately 3.5 cm from the introitus (for 3 out of the 4 subjects).Pressure increases ranged from 23 mmHg to 120 mmHg. Pressure profilesfor cough and Valsalva showed the greatest pressure increase at the mostdistal sensors which would be measuring abdominal pressure. Maximumabdominal pressures were in the range of 70 mmHg to 120 mmHg for coughand 30 mmHg to 85 mmHg for Valsalva. The greatest rate of pressurechange was 605 mmHg/s recorded for cough. Due to the small sample size,no statistical analysis could be performed.

The testing shows that the IVPSD is able to accurately measure thevaginal pressure profile and there are distinctive pressure profiles forthe baseline and for each task. Evidence suggests that the IVPSD cancapture the differences between abdominal pressure, PFM pressure andatmospheric pressure. In-vivo movement of the device needs to beaccounted for, which may be done using signal processing or throughchanges to the physical shape design. A sampling frequency of 140 Hz wassufficient to capture rapid pressure changes, as experienced forcoughing.

The testing also showed that the IVPSD is capable of simultaneousmeasurement of abdominal pressure and PFM pressure, producing a vaginalpressure profile, and has great potential for the IVPSD to be used asboth an effective PFMT tool, and as an aid for clinician to define preand post-surgical vaginal pressure profiles.

Unless the context clearly requires otherwise, throughout thedescription, the words “comprise”, “comprising”, and the like, are to beconstrued in an inclusive sense as opposed to an exclusive or exhaustivesense, that is to say, in the sense of “including, but not limited to”.

Although this invention has been described by way of example and withreference to possible embodiments thereof, it is to be understood thatmodifications or improvements may be made thereto without departing fromthe scope of the invention. The invention may also be said broadly toconsist in the parts, elements and features referred to or indicated inthe specification of the application, individually or collectively, inany or all combinations of two or more of said parts, elements orfeatures. Furthermore, where reference has been made to specificcomponents or integers of the invention having known equivalents, thensuch equivalents are herein incorporated as if individually set forth.

Any discussion of the prior art throughout the specification should inno way be considered as an admission that such prior art is widely knownor forms part of common general knowledge in the field.

1. A pressure sensor apparatus comprising: a plurality of pressureresponsive chambers provided along a first dimension of the apparatus;and a pressure sensor device provided in each chamber.
 2. The pressuresensor apparatus as claimed in claim 1 wherein the chambers are arrangedsuccessively along the first dimension such that the pressure sensordevice may simultaneously sense pressure to thereby provide a pressureprofile along the first dimension.
 3. The pressure sensor apparatus asclaimed in claim 1 wherein the first dimension comprises a longitudinaldimension of the apparatus.
 4. The pressure sensor apparatus as claimedin claim 1 wherein each chamber comprises at least one pressuretransmitting wall.
 5. The pressure sensor apparatus as claimed in claim1 wherein a pressure resistant barrier is provided between adjacentchambers.
 6. The pressure sensor apparatus as claimed in claim 5 whereinthe pressure resistant barrier is sufficient to substantially preventpressure changes in one chamber affecting pressure in the adjacentchamber.
 7. The pressure sensor apparatus as claimed in claim 1 whereineach chamber is filled with a fluid whereby the pressure sensor devicesenses the pressure of the fluid in the chamber.
 8. The pressure sensorapparatus as claimed in claim 7 wherein the fluid comprises air.
 9. Thepressure sensor apparatus as claimed in claim 1 wherein the apparatusfurther comprises a data transfer apparatus to provide the sensedpressure from each sensor to a further apparatus.
 10. The pressuresensor apparatus as claimed in claim 9 wherein the data transferapparatus comprises a transmitter.
 11. The pressure sensor apparatus asclaimed in claim 1 wherein the apparatus further comprises a retentioncontour for retaining the apparatus in an anatomical cavity in use. 12.The pressure sensor apparatus as claimed in claim 11 wherein theretention contour extends in a second dimension which is substantiallytransverse to the first dimension.
 13. The pressure sensor apparatus asclaimed in claim 11 wherein the retention contour comprises one or moreribs or wings dependent from the apparatus.
 14. The pressure sensorapparatus as claimed in claim 1 wherein the apparatus comprises anintra-abdominal pressure sensing device.
 15. The pressure sensorapparatus as claimed in claim 1 wherein the apparatus comprises anintra-vaginal device.
 16. A method of measuring pressure in ananatomical cavity comprising simultaneously sensing pressure at aplurality of locations along a first dimension of the cavity andrecording the sensed pressure measurements to provide a pressureprofile.
 17. The method as claimed in claim 16 further comprisingrepeating the method.
 18. The method as claimed in claim 16 furthercomprising performing the method under different conditions imposed onthe anatomical cavity. 19.-20. (canceled)